Furnace



J. F. O. STRATTON FURNACE Aug. 23, 1927. ,158

Filed Aug. 28. 1925 4 Sheets-Sheet 1 #5200225? Lfoizrzffl 5222222571.

1927' J. F. o. STRATTO'N FURNACE Filed Aug. 28. 1925v 4 Sheets-Sheet 2Aug. 2

J. F. O. STRATTON FURNACE Filed Aug. 28. 1925 4 Sheets-Sheet 3 1927' J.F. o. STRATTON FURNACE Filed Aug. 28

1925 4 Sheets-Sheet 4 Patented Aug. 23, 1927.

PATENT OFFICE.

JOHN F. O. STBA'ITON, 01 CHICAGO, ILLINOIS.

runner.

Application filed August 28, 1925. Serial No. 52,998.

The present invention relates to improvements in. furnaces, and hasparticular reference to furnaces of the type disclosed in my Patent No.1,505,505, issued August 19,

That patent discloses a vertical jetfurnace in which a blast or jet ofair is directed upwardly through the throat into the combustion chamber.The blast of air agitates the fuel which is fed in at the top of thefurnace, raises or holds it in suspension to secure complete combustion,and separates the combustible from the non-combustible portions. Tocreate this blast, air under 5 pressure is admitted to the ash pit whichserves as a pressure chamber, and from there passes through a longnarrow space defined by a pair of parallel intercepting memberspreferably consisting of grate bar construction and directly underlyingthe throat. In entering the ash pit, the air passes over the outsidesurfaces of the walls of the throat and through and over theintercepting members, thereby cooling the same. The intercepting membersare continuously reciprocated in unison to shift the region of the blastback and forth across the throat, thereby reaching all portions of thefuel and keeping them in mobile condition. The

non-combustible portion of the fuel falls through the space between theintercepting members into the ash pit.

I have found that slag falling at the sides of the throat onto theintercepting members tends to adhere thereto, thereby preventing properagitation of the fuel bed, and preventing air from passing through thegrates in said members to clean and cool the latter. An important objectof the present invention therefore resides in the provision of means forautomatically cleaning the intercepting members.

A more specific object is to provide for one or each of the interceptingmembers, a cleaning or slicing member reciprocable thereon andoppositely thereto to clean the associated intercepting member andinci-' dentlv to stir and agitate the material in the throat.

When the furnace is in operation, molten slag runs down the inclinedwalls into the throat and onto the slicing members and interceptingmembers where it solidifies due to the chilling from the comparativelylowtemperature of the intercepting members and the low-temperature airpassing through these. If the region of the blast is shifted to thesides of the throat, the relatively cold air will chill the slag andcause it to solidify before reaching the bottom of the throat, andusually at or just above the upper edges of the throat. Upon solidifyingthe sla tends to adhere to the inclined walls, an

gradually a. ma of solid slag will collect at opposite sides of thethroat, thereby lowering the efliciency of the furnace and necessitatingfrequent cleaning. An important object of the present inventiontherefore is to provide a furnace of the above character in which theintercepting members are given a stroke substantially less in lengththan the width of the throat and in a central range spaced from thesides of the throat; and in which each slicing member is moved asubstantial distance into the throat to the adjacent edge of the spaceas the latter is shifted in the opposite direction into its extremeposition at that side of the throat, thereby slowly shoving the cooledmatter on the underlying intercepting member into the blast to causeaseparation of the combustible and non-combustible portions.

Further objects are to provide means for scraping the slicing members.as they are being withdrawn from the throat, and to provide means forvarying the movements of the parts. a

Still another object is to provide scraping members for the slicingmembers, and serving also to ash pit outwardly over the slicing members.A general object is to provide a new and improved furnace which issimple and sturdfiy in construction, and. which is highly e cient inoperation.

Further objectsand advantages will be come apparent as'the descriptionproceeds.

In the accompanying drawings, Figure 1 is a vertical sectional view of afurnace embodying the features of my invention.

Fig. 2 is a fragmentary enlarged section- 211 view taken along line 2-2of Fig. 6.

Fig. 3 is a horizontal sectional view of the throat taken along line 33of Fig. 1.

Fig. 4 is a plan view of the throat.

Fig. 5 is a horizontal sectional view'taken along line 5-5 of Fig. 1 andshowing the operating mechanism.

direct the air entering the Fig. 6 is a sectional view taken along line6-6 of Fig. 4.

Fig. 7 is a fragmentary front View of a part of the operating mechanism.

While the invention is susceptible of various modifications andalternative constructions, I have shown in the drawings and will hereindescribe in detail the preferred embodiment, but it is to be understoodthat I do not thereby intend to limit the invention to the specific formdisclosed but aim to cover all modifications and alternativeconstructions falling within the spirit and scope of the invention asexpressed in the appended claims.

Referring more particularly to the drawings, while the main body of thefurnace may conform to any suitable construction, it preferablycomprises a front wall 10, a rear or bridge wall 11, and inclined frontand rear bottom walls 12 and 13, respectively. The space bounded bythese walls constitutes a combustion chamber 14. Fuel, such as coal 15,may be continuously fed from a hopper 16 having a feed screw 17 througha spout 18 in a set oil of the front wall 10 into the upper part of thecombustion chamber 14. The front wall 10 is provided with an opening 19having a closure 20, and through which fuel may be thrown into thefurnace by hand at any time. The inclined walls 12 and 13 are lined withsuitable refractory material, such as bricks or blocks and converge tothe upper edges of a long narrow throat 21. The inclined walls serve todirect coal and slag falling thereon into the throat.

Located at the lower portion of the furnace and bounded by four walls22, 23, 24 and 25 is an ash pit 26 which also serves as an air pressurechamber. Ashes may be removed from the pit 26 through an opening 27 inthe wall 22 normally closed by the door 28.

The throat 21 is constructed of a plurality of sections which fitclosely together. and which preferably consist of blocks 29 shaped toform straight parallel side walls. and blocks 30 shaped to form curvedend walls. The upper edges of the blocks 29 and 30 are curved orinclined, as indicated at 31, to

form short continuations of the inclined walls 12 and 13, and the sidesthereof extend vertically below said edges preferably for av distance ofabout six inches. This depth is preferred to a shorter depth since itsubstantially equals that which a suitable banked coal fire would have.As a result, the banked fire bed would have straight vertical sides, andif congealed could still. be easily removed. By increasing the depth ofthe throat, the inclined walls 12 and 13 are also brought nearer to theexpanding blast of air and to the area of combustion, therebymaintaining the fuel and slag on the walls at a higher temperature, andpreventing fuel from passing along the walls beyond the range of theblast into the throat.

The blocks 29 and 30 are hollow metal castings capable of withstandingextremely high temperatures. Each side block 29 is formed with an airpassage 32 having a downwardly extending nozzle 33 opening into the ashpit 26 at the lower end of the throat. The outer wall of the nozzle 33terminates a short distance above the inner wall to permit lateraldeflection of the discharged air. Surrounding the blocks 29 and 30constituting the throat 21 is an air chamber 34 which communicates withthe air passages 32. The air chamber 34 includes passages 35 around theend blocks 30 to connect, the side spaces. In the present instance, eachpassage 35 is con structed of an upper wall .36, a lower wall 37 and anend wall 38, the upper and lower walls extending up to the end blocks30. Preferablythe inner edge of the lower wall 37 is spaced a smalldistance from the end blocks 30 to provide a narrow opening 39 adaptedto permit the escape of a small amount of air for cooling purposes. Oneside of the air chamber 34 is connected to an intake conduit 40 of anysuitable shape adapted to receive compressed air from a suitable source(not shown). The inner walls of the blocks 29 and 30 are corrugated asshown to provide extensive outer cooling surfaces over which theincoming air must pass, and to compersate for any variations due toexpansion or contraction. Air entering the chamber 34 will be dischargedthrough the nozzles in to the ash pit 26 to maintain a predeterminedpressure therein. 15y constructing the throat 2-1 of a plurality ofhollow castings, of which the side castings have independent airpassages and discharge nozzles, the discharge is uniformly distributedin fixed jets about the throat, thereby producing a uniform coolingeffect. The air chamber 34 thus constitutes a form of heat exchangeserving to cool the wallsof the throat 21 and to preheat the air to beused in combustion. The air cooled throat herein described is fullydisclosed and claimed in my copend-ing application Ser. No. 52,999,filed August 28, 1925.

The air chamber 34 and throat 21 may be supported in any suitablemanner, and in the present instance are mounted at opposite ends on fourchannel shaped columns 41, the walls 36, 37 and 38 being rigidly securedthereto. These columns extend up from masonry columns 42 built in fromthe side walls 24 and 25 of the ash pit 26.

Mounted on each of the columns 41. is one of a plurality of inwardlyextending brackets 43 supporting a pair of parallel spaced tracks 44 and45. Each track preferably comprises two closely spaced parallel invertedT-shaped beams or bars. Movtracks are a plurality of anti-frictionmembers, each of which consists of a pair of peripherally groovedsheaves 46 riding on the edges of the T- sha ed beams and rigidlyconnected by a shaft 47. In the present instance, four antifrictionmembers, one on each end of each track are provided. Mounted for bodilyreciprocation on the friction members is a pair of tracks 48 and 49 eachof which comprises two parallel bars connected together by means ofspacers 50, and engaging the peripheral grooves in the sheaves 46. Thefront ends of the bars of each of the tracks 48 and 49 are bent towardeach other,"and are connected by a pin 51 to which the rear end of anoperating link 52 is pivotally secured.

Mounted on the tracks 48 and 49 for re-' ciprocation therewith acrossthe front portion of the throat is an intercepting member 53 whichcomprises a rectangular frame 54 having end brackets 55 rigidly securedto the tracks. A second intercepting member 58 having a similar frame 59is mounted for reciprocation across the rear portion of the throat 21.The frame 59 however is not rigidly secured to the tracks 48 and 49, butis provided with end brackets 60 in which rollers or sheaves 61 aremounted. The sheaves 61 engage the inner bars of the tracks 48 and 49for adjustment toward and from the first mentioned frame. A plurality ofgrate bars 62 are mounted in the frames 54 and 59, and are formed withside lugs 68 to provide the usual spacing. The intercepting members 53and 58 are spaced apartto define a long narrow space or passage 64serving as a nozzle for directing a blast of air from the ash pit 26into the combustion chamber 14. To provide means for adjusting the widthof the space 64, and for reciprocating the frame 59 with the tracks 48and 49, the brackets 60 are formed with upstanding lugs 65 to which therear ends of two spaced adjusting links 66 are pivotally secured.

Two cleaning or slicing members 67 and 68 are provided for dislodgingslag and other material adhering to or collecting on the interceptingmembers 53 and 58 respectively. The members 67 and 68 comprise aplurality of slicing grates 69, the free inner ends of which arerespectively reciprocable in the front and rear sides of the throat andon the underlying grates 62 to and from the front and rear edges ofthespace 64, and the outer ends of which are formed with hooks 70fitting respectively over two horizontal shafts 71 and 72 extendingalong opposite sides of the throat. The front shaft 71 is mounted in thefree upper ends of two spaced arms 73 pivotally mounted at their lowerends on the front brackets 43 at opposite sides of the ash pit 26. Thearms 73 ably mounted on the are pivotally connected near their upperends by means of studs 74 to the rear ends of two operating links 7 5.The rear shaft 72 is similarly mounted on arms 76 sup ported by rearbrackets 43 and pivotally connected by means of studs 77 to twooperating links 78. The slicing grates 69 are formed with side lugs 79to provide the usual spacing and are dimensioned to extend be-' yond thesides of the-throat 21 in all positions of reciprocation. The ends ofthe intercepting members and slicing members also extend beyond the endsof the throat 21. The grates 62 and 69 permit small amounts of cold airto percolate through the intereepting members and slicing members tocool the latter and to cause the slag falling thereon to harden. Whilegrates preferably are employed, it is to be understood that any othersuitable means having small openmgs for the passage of air may beemployed.

To prevent fuel orslag from being carried on the grates 69 out of thethroat 21, a plurality of scraper members 80 are provided. In thepresent instance, four scraper members are provided, and each membercomprises a bar 81 extending along one half of one side and curvedpartially around one end of the throat 21, and a pair of spaced arms 82pivotally secured in brackets 83 on the under side of the air chamber34. The bars 81 rest on the grates 69 directly beneath the nozzles 33,and each bar is formed with an upstanding flange 84 for deflecting partof the air from the nozzle overhead outwardly over the surfaces of thegrates 69. Air thus passes over and through the grates 69 to cool thelatter.

The front ends ofthe links 52, 66, 75 and 78 are pivotally connected tofour pairs of levers 85, 86, 87 and 88 mounted on four shafts 89, 90, 91and 92 respectively. These shafts extend transversely in the front ofthe ash pit 26, and through air tight bearings 93 in' the side wall 25into a chamber 94 open at the top to the atmosphere, and are journaledin spaced bearing brackets 95. and 96 in opposite sides of the ash pitand in a bearing bracket 97 in the chamber 94. The levers extendupwardly from the shafts so as to have a horizontal throw. and aresubject to adjustment as will be hereinafter described. Secured to theends of the shafts 89, 90, 91 and 92 in the chamber 94 are foursubstantially horizontally disposed lever-S 98, 99, 100 and 101respectively which are pivotally connected to the lower ends of fourlinks 102, 103, 104 and 105 respectively, extending vertically through ahole 106 in the floor 107 at the front of the furnace. The levers 98 and101 extend forwardly. and the levers 99 and 100 extend rearwardly sothat upon movement of the links 102. 103, 104 and 105 in likedirections, the intercepting members and the slicing members will bereciprocated in opposite directions.

At their upper ends, the links 102, 103, 104 and 105 are adjustablyattached vrespectively to four horizontally extending sector plates 108formed in )arallel spaced relation on a plate 109 pivota ly mounted in asupporting standard 110. Each sector plate 108 is formed with an arcuateslot 111 in which a bolt 112 is adjustably mounted. One end of the bolt112 is pivotally secured to one of the links 102, 103. 104 and 105. andthe other end is provided with a hand wheel nut 113 for clamping thebolt in ad justed position in the slot 111. The bolt is also providedwith a hand lever 114 whereby it may be moved in the slot 111 when thenut 113 is loosened either to effect an adjustment or to manuallyoperate the associated link. It will be evident that by adjusting thevertical links, the levers on the horizontal shafts in the ash pit 26will be adjusted angularly, thereby changing their position and alsochanging the horizontal or effective component of their throw for agiven angular movement. The plate 109 is formed with a downwardlyextending arm 115 which is connected through a link 116 to a crank arm117 of a reduction gearing 118 driven by any suitable means (not shown).The operating mechanism herein described for the tracks and the gratesis fully disclosed and claimed in my copending application Ser. No.53,000, filed August 28, 1925.

The adjustment is such that the frame 59 is .reciprocated throughsubstantially the same distance as the tracks 48 and 49 to maintain thespace 64 at a fixed Width throughout the operation. The space 64 isshifted only across the central area of the throat, and the slicingmembers are periodically projected a substantial distance into thethroat to meet the space at a substantial distance from the sides. Thethroat is constructed of a width permitting however a substantialmovement of the space 64.

In operation of the furnace, crushed fuel 15 is charged into the furnacefrom the spout 18 in the form of a falling stream.

The fuel may be initially ignited in any well known manner as by the useof gas jets or other equivalent devices.

Air enters through the conduit 40 into the .air chamber 34. a portion ofthe air passing downwardly through the adjacent nozzles 33 in the sideblocks 29, and the remaining portion passing around the end blocks 30 tothe nozzles 33 on the remote side of the throat 21. A small amount ofair also passes through the end openings 39 into the ash pit. In passingaround the outer surfaces of the corrugated walls of the end blocks 29and 30 and through the nozzles 33 and openings 39, the air cools thewalls of the throat, thereby preventing overheating. Part of the airdischarged from the nozzles 33 passes through the spaces between thegrates 62 and 69, and part is laterally deflccted by the scrapingmembers 80 to pass over the surfaces of the grates 69, into the ash pit26, thereby cleaning and cooling the grates. From the ash pit, the airis forcibly discharged in the form of a blast through the space 64between the intercepting members 53 and 58 into the combustion chamber14. The blast of air expands and tends to hold the fuel in suspension.The course of the air is indicated in the drawings by arrows.

The fuel is consumed while in suspension. Parts of the fuel fall on theinclined Walls 12 and 13, and are directed thereby into the throat 21.-Molten slag runs down the inclined walls into the throat and onto thegrates 62 and 69. The slag there is caused to solidify by the relativelycold air percolating up through the spaces between and cooling thegrates. The non-combustible material has a greater specific gravity thanthe incandescent and partially volatilized combustible material. Apressure is maintained in the ash pit such that the force of the blastof air will allow the non-combustible material to fall through the space64 into the ash pit, and will retain.the combustible material insuspension. The width of the space 64 between the intercepting Incinberscan be adjusted by adjusting the connection between the link 103 and theassociated sector plate 108, and the range of-reciprocation can likewisebe adjusted by adjusting the links 102 and 103 relative to the sectorplates.

The intercepting members 53 and 58 are reciprocated to shift the regionof the blast of air slowly back and forth across the throat, but not tothe very sides of the throat. By shifting the region of the blast of airall parts of the fuel in the furnaces are reached. The slag and fuel onthe grates 62 are dislodged and moved into the blast of air by theslicing grates 69 which are reciprocated oppositely to the members 53and 58, thereby cleaning the grates and also agitating the material topermit efficient separation. Thescraping members 80 serve to clean theslicing grates 69. By cleaning the grates 62 and 69 efiicientcooling ispermitted. The range and extent of reciprocation of the slicing gratescan be adjusted through the links 104 and 105.

Upon loosening-the nuts 113, the above parts can be selectively operatedmanually by means of the hand levers 114.

It will be evident that I have provided an efiicient vertical jetcombustion furnace capable of fine adjustments to suit differentoperating conditions, and not likely to get out of order.

Lil]

I claim as my invention:

1. A furnace having, in combination, a combustion chamber, a throatformed in'the bottom of said combustion chamber, an air pressure chamberbelow said throat, movable intercepting means directly beneath saidthroat, said interceptingmeans consisting of a plurality ofindependently movable sections spaced apart to define a space fordirecting a blast of air from said pressure chamber into said combustionchamber, means for moving said sections in unison to shift said spaceback and forth across said throat, and means movable oppositely to saidsections and overlying the same to dislodge matter collecting thereon.

2. A furnace having, in combination. a combustion chamber, a throatformed in the bottom of said combustion chamber, an air pressure chamberbelow said throat, movable intercepting means directly beneath saidthroat, said intercepting means consisting of a plurality ofindependently movable sections spaced apart to define a space fordirecting a blast of air from said pressure chamber into said combustionchamber, means for moving said sections in unison to shift said spaceback and forth across the throat, the range of said movement beingsubstantially less than the width of said throat, and meansautomatically operable to .clean said sections.

3. A furnace having, in combination, a combustion chamber, a throatbelow said combustion chamber, an air pressure chamber below saidthroat, movable intercepting means directly beneath said throat, saidintercepting means consisting of a plurality of independently movablesections spaced apart to define a space for directing a blast of airfrom said pressure chamber into said combustion chamber, means formoving said sections in unison to shift said space back and forth acrosssaid throat, including a pair of slicing members positioned on saidsections, and means for moving said slicing members oppositely to saidsections to dislodge matter collecting on the latter.

4. A furnace having, in combination, a combustion chamber, a throatformed in said combustion chamber, an air pressure chamber below saidthroat, movable intercepting means directly beneath said throat, saidintercepting means consisting of a plurality of independently movablesections spaced apart to define an opening for directing a blast of airfrom said pressure chamber into said combustion chamber, means formoving said sections to shift said opening transversely of said throat,a slicing member on one of said sections, and means for moving saidslicing member over said last mentioned section to remove materialtherefrom.

5. A furnace having, in combination, a combustion chamber, having athroat, an air pressure chamber below said throat, movable interceptingmeans directly beneath said throat,-said intercepting means consistingof a plurality of independently movable sections spaced apart to definea space for directing a bla t of air from said pressure chamber intosaid combustion chamber, means for reciprocating said sections to shiftsaid space transversely of said throat, a slicing member on one of saidsections. and means for reciprocating said slicing member continuallyand oppositely to said last mentioned section to remove material on thelatter.

6. A furnace having. in combination, a combustion chamber, having athroat, an air pressure chamber below said throat, movable interceptingmeans directh beneath said throat, said intercepting means consisting ofa plurality of inde 'iendcntlv movable sections spaced apart to define anozzle for directing a blast of air from said pressure chamber into saidcombustion chamber, means for reciprocating said sections in unison toshift said nozzle baclc and forth transversely of said throat, a pair ofslicing members movable on said sections and oppositely thereto, andmeans for reciprocating said slicing members. i

7.. A furnace having. in combination. a

combustion chamber having an opening in the bottom thereof. an airpressure chamber below said opening. movable intercepting meansinterposed between said chamber and said opening. said means consistingof a plurality of independent spaced sections, means for moving saidsections to change the position of the space thcrcbetween under saidopening, slicing members interposed between said sections and saidopening, means for moving said slicing members over said sections toclean the latter. and means positioned to clean said slicing members. 8.A furnace having, in combination, a combustion chamber having an openingin the bottom thereof, an air pressure chamber below said opening,movable intercepting means interposed between said chamber and saidopening, said means consisting of a. plurality of independent spacedsections. means for moving said sections to change the position of thespace thcrehetwecn, a pair of slicing mt-mbers interposed between saidsections and said opening, and means for mov ing said slicing membersover said sections to clean the latter.

9. A furnace having, in combination, a combustion chamber having anopening in the bottom thereof, an air pressure chamber below saidopening, a plurality ot spaced apart intercepting members interposedbetween said chamber and said opening. the space between said membersserving as noz- Zle means for directing a blast of air of predeterminedsize and force through said opening into said comlmstiou chamber,

means for adjusting said members relative to each other to change thesize of said space and for moving said members in unison to change theposition of said space beneath said opening, and means automaticallyoperable to clean said members.

10. A furnace having,'in combination, a combustion chamber havin athroat opening, an air pressure cham er communicating with said opening,a pair of spaced apart members disposed across said opening and servingto direct a blast of air from said pressure chamber into said combustionchamber, a pair of cleaning members (lisposed at opposite sides of saidthroat and interposed between said first mentioned members and saidopening, and means for moving said first mentioned members and saidcleaning members relative to each other, and for moving said firstmentioned members across said opening, whereby said blast is shiftedinto different positions and said first mentioned members are cleaned.

11. A furnace having, in combination, a combustion chamber having athroat opening, an air pressure chamber communicating with said opening,a pair of spaced apart members disposed across said opening and servingto direct a blast of air from said pressure chamber into said combustionchamber, a pair of slicing members interposed between said firstmentioned members and said opening, and means for reciprocating'saidfirst mentioned members under said opening to shift the blast and forreciprocating said first mentioned members and said slicingmembersrelatively to each other to clean theformer.

12. A furnace having, in combination, a combustion chamber having athroat opening, an air pressure chamber communicating with said opening,a pair of spaced apart members disposed across said opening and servingto direct a blast of air from said pressure chamber into said combustionchamber, a pair of cleaning members interposed between said firstmentioned members and said opening, means for reciprocating said firstmentioned members under said opening to shift the blast and forreciprocating said first mentioned members and said cleaning membersrelatively to each other to clean the former, and means forindependently adjusting the movements of said members.

13. A furnace having, combustion chamber having a throat opening, an airpressure chamber con'ununicating with said opening, a pair of spacedapart members disposed across said opening and serving to direct a blastof air from said pressure chamber into said combustion chamber, a pairof cleaning members on said first mentioned members, means forreciprocating said first mentioned members under intercepting means toshift in combination, a

said opening to shift the blast and for reciprocating said firstmentioned members and said cleaning members relatively to each other toclean the former, and scraping members disposed at opposite sides ofsaid opening and resting on said cleaning members for cleaning thelatter.

1%. A furnace having, in combination, a combustion chamber having anarrow opening in the bottom thereof, an air pressure chamber below saidopening, intercepting means directly below said opening and defining anarrow longitudinal space for admitting air in the form of a blast fromsaid pressure chamber into said combustion chamber, means on saidintercepting means for cleaning the latter, and means for moving saidintercepting means to shift said space and for moving said interceptingmeans and said cleaning means relatively to each other to clean saidintercepting means.

15. A furnace having, in combination, a combustion chamber having anarrow opening in the bottom thereof, an air pressure chamber below saidopening, intercepting means directly below said opening and defining anarrow longitudinal space for admitting air in the form of a blast fromsaid pressure chamber into said combustion chamber, means on saidintercepting means for cleaning the latter, means for moving said a saidspace and for moving said intercepting means and said cleaning meansrelatively to each other to clean said intercepting means, and meansresting on said cleaning means for dislodging matter collecting on thelatter.

16. A furnace having, in combination, a combustion chamber having anopening, an air pressure chamber communicating with said opening,intercepting means disposed across said opening, said intercepting meansdefining a space constituting a nozzle for admitting air from saidpressure chamber into said combustion chamber, means for reciprocatingsaid intercepting means, and means resting on said intercepting meansfor cleaning the latter at each end of its reciprocation.

17. A furnace having, in combination, a combustion chamber having athroat opening in the bottom thereof, a pressure chamber below saidopening, intercepting means disposed across said opening and controllingthe passage of air from said pressure chamber into said combustionchamber, and a pair of slicing members disposed at opposite sides ofsaid opening and reciprocable over said intercepting means to clean thelatter.

18. A furnace having, in combination, a combustion chamber having athroat opening in the bottom thereof, a pressure chamber below saidopening, intercepting means reciprocable acros said opening, saidintercepting means defining a space for directing air from said pressurechamber in the form of a blast through said opening into said combustionchamber, means for reciprocating sa-id intercepting means to shift saidblast back and ,forth across said opening, the range of saidreciprocation being substantially less than the Width of said opening inthe direction of said reciprocation, a pair of slicing members disposedat opposite sides of said opening and reciprocable on said interceptingmeans, and means for reciprocatin said slicing members oppositely tosaid intercepting means, said last mentioned reciprocation causing saidslicing members to be alternately moved laterally into said throatopening to the side edges of said space for the purpose of cleaning saidintercepting means.

19. A furnacehavmg, in combination, a-

combustion chamber, a throat in the bottom thereof, a pressure chambercommunicating With said throat, intercepting means disposed across thethroat opening, said intercepting means defining a space for admittingair from said pressure chamber into said combustion chamber and having aplurality of small restricted openings, means for admitting air to saidpressure chamber, cleaning members disposed at opposite sides of saidthroat and having a plurality of small openings, said members resting onsaid intercepting means for removing ma terial collecting on the latter,and means associated with said last mentioned means and operative todirect part of the lncoming an over the surface of said mterceptmg meansand said members and part of the inv coming air through said openingsinto said pressure chamber to cool said intercepting means and saidmembers.

20. A furnace having, in combination, a combustion chamber having athroat, intercepting means positioned across said throat, and defining aspace opening into said throat, a pressure chamber communicating throughsaid space with said throat, means for reciprocating said interceptingmeans to shift said space back and forth across said throat but througha range substantially less than the width of said throat in the line ofreciprocation, a slicing member at one side of said throat and restingon said intercepting means, and means for reciprocating said slicingmember oppositely to said intercepting means and in a range such that itis projected periodically into said throat to the edge of said space.

21. A furnace having, in combination, a combustion chamberhaving athroat opening in the bottom thereof, means for 'creating an upwardlydirected blast of suflicient force to erupt fuel falling to the bottomof said combustion chamber into said throat, means for confining saidblast to a predetermined area less than the cross sectional areaofsaidthroat, means for moving said last mentioned means transversely of saidthroat to shift the region of said blast, said blastconfining meansbeing positioned substantially below said throat, and meansautomatically operable to clean said blast confining means.

In testimony whereof, I have hereunto affixed my signature.

JOHN F. o. STRATTION.

